Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
The fact that fly fishermen need broad principles of biology, not a collection of exceptions, makes it difficult to handle this family.
In 4189 records from GBIF, adults of this family have mostly been collected during July (24%), June (23%), August (15%), May (15%), September (8%), and April (7%).
In 2081 records from GBIF, this family has been collected at elevations ranging from -30 to 38927 ft, with an average (median) of 1921 ft.
Diet: Algae, decaying leaves and wood, decaying animals
Shelter type: Tube with silk on the inside and plant matter, sand, or gravel on the outside
In the early or mid summer, the larvae reach maturity and move from the faster currents to the slower flows that are generally found along the margins of the stream. Then they attach their cases to the rocks, seal themselves inside, and begin pupation. This transformation takes about two months. When the pupae are ready to emerge anytime between late afternoon and dark, they chew open the front of their cases and swim or crawl to the surface. The ones that find exposed rocks cling to them close to or just above the waterline; their pupal shucks split open and the adults emerge. Larvae that took refuge and pupated behind unexposed mid-stream rocks pupate and emerge in the open water. Most pupae emerge from waters that are too shallow or too exposed for trout. Any pupae that emerge in deep or open waters are vulnerable as they swim to shore or the surface.